Rear:
If your okay with sacrificing 5 mph top speed, an m10 is still a good swap. Plus the information you need is everywhere.
Stay away from the mid to late 2000s Polaris m10s with the tubular arms. Nothing wrong with tubes per se, but these skids are not built as well and are prone to cracking.
M10 needs to be setup correctly. When it is, you get a great ride.
Or: 2002 and up Polaris "edge" skids, fusion skids, Dragon skids, even new indy skids. They are conceptually and geometrically the same. Just detail changes and trim changes thru the years.
******No matter what you choose, the shocks need to be fresh and valved correctly. Correctly as in, at least to OEM spec******
In all honesty you could swap any skid. Even an r motion. But with the edge style and m10 you are scaffolding off over 10 years of swap knowledge on the web. So it's just easier.
Front shocks:
The front of your machine thankfully has a modern level of travel and decent geometry. So you just need shocks, or your shocks serviced.
Check out this guy below...he builds and sells fox aluminum body and steel body shocks. Internal floating piston or reservoir. Great prices and he knows all the oem valve codes, shock length and bushing sizes for the older stuff.
http://snorunner.byethost9.com
Hygear and Monster performance are good too. Though I think they cator to newer sleds more.
With the front shocks, request the big heavy duty fox bottom out bumpers. They make a big difference. You can have a more compliant ride with good bottom resistance. It's like dual rate springs. They even make dual rates better too.
Another thing that helps is getting your bars up to a more modern level and raising the seat. Grafting a fusion seat or some other higher seat is a big benefit.
I built a 2000 Indy 500xc sp with a lifted fusion seat, m10, bar risers and good front shocks. I had 3 Great seasons on that sled and liked it. So much so that my 2011 ski doo xp was a little disappointing until I got the shocks upgraded. Especially the front.
If you have any questions, just ask.